Extended Data Fig. 10: CuB potentially provide a carbon source for promotion of Enterobacter growth.
From: Root-secreted bitter triterpene modulates the rhizosphere microbiota to improve plant fitness
a, The profiles of CuB content in TSB medium after 3 days of culture with the indicated Enterobacter strains. A significant decrease in CuB level was observed in the medium cultured with Enterobacter strains, compared to that of TSB medium without Enterobacter strain (CK). Data are represented as mean ± SD (n = 3). b and c, HPLC-QTOF-MS analysis of the E-159 medium supplemented with CuB. b, Metabolic profiling analysis of extracts prepared from E-159 medium. The medium supplemented with only CuB (CuB + medium) or without CuB but containing E-159 strain (E-159 + medium) was considered as negative control. CuB was dissolved in methanol, and equal-volume methanol was added for each treatment. Two specific peaks (indicated by CuB derivate), at retention time of 2.64 and 2.72 min, respectively, were detected in the E-159 medium supplemented with CuB. TIC, total ion chromatograms; EIC 558.3421, extracted a characteristic fragmental ion of the CuB derivates at m/z of 558.3421. c, Comparison of the mass spectrum between CuB derivates and CuB standard. Although the mass spectra of CuB derivates and CuB shared the same quasi-molecular ion peak at m/z 576, the ion signal in CuB derivates were deciphered as a hydron plus CuB derivate ([M + H]+), while the ion signal in CuB it was suggested to be an ammonium cation plus CuB ([M + NH4]+).
